Coupling unit



h'Nov. 26. 1929. B. VAN DER POL.

COUPLING UNIT Filed May 22, 1925 stations.

Patented Nov. 26, 1929 UNITED STATES PATEN'r opi-*ics BALTHASAR VAN DER POL, OF EINDHOVEN, NETHERLANDS, ASSIGNOR, BY MESNE.

ASSIGNMENTS, TO RADIO CORPORATION OF AMERICA, OF NEW YORK, N. Y., A COR- PORATION OF NEW YORK COUPLING UNIT Application led May 22, 1925, Serial No. 32,130, and in the Netherlands .Tune 20 1924.

This invention relates to an apparatus adapted for use in amplifying installations operating with discharge tubes provided with three or more electrodes, such as are used for receiving wireless signals.

In such amplifying installations the cui'- rent variations occurring in the anode circuit of a tube may be transmitted in the forni of tension variations to the circuit of the controlling grid of a next tube by means of a transformer, condenser or ohmic resistance. The latter method in which the ohmic resistance, which hereinafter will be referred to as an anode resistance, is connected in the anode circuit presents the advantage that the oscillations received do not become deformed, which is the case when using a condenser and especially when using a transformer having an iron core.

According to the invention such an anode resistance is combined with the corresponding grid condenser and a leakage resistance to form a self-contained unit, in which the grid condenser is connected to one end of each resistance, whereas the two ends of each resistance are connected to contact-making members such as terminals, contact pins oi' the like, by means of which the apparatus can be connected in the amplifying installation.

The apparatus according to the invention may take very reduced dimensions and be, for example. of about the same size as the receiving valves used in wireless receiving The apparatus according to the invention can easily be so executed that it has externally the same shape as such receiving valves.

According to the invention, the anode resistance, the grid condenser and the leakage resistance are arranged within a closed exhausted vessel. This presents the advantage that the component members are absolutely prevented from becoming moist which is essentially prejudicial to the condenser. Further, the apparatus according to the invention may be provided with a contact plug having four contact-pins by means of which it can be connected to the amplifying installation.

In a suitable embodiment of the inventiontlie grid-condenser may be constructed as aL wound condenser and be arranged within a vessel of insulating material, on the outer wall ofv which the two resistancesare wound. In this case the said resistances preferably consist of a resistance wire helically wound on, a core of insulatingmaterial` The invention may be clearly understood by reference to the accompanying drawing. In the said drawing:

Fig. 1 is a portion of an amplifying installation in which resistance amplification is. made use of.

Fig. 2 shows an embodiment of the invention in which the external shape of the apparatus is similar to that of a receiving valve for wireless receiving stations.

Fig. 3 is a different construction which likewise resembles externally a receiving valve and in which the electric component members are arranged within a4 closed exhausted vessel.

Referring to Fig. 1 a discharge tube 1 has an incandescent cathode, 2, a controlling grid 3 and an anode 4. The oscillations-which are received by the grid 3 in any suitable manner set up current variations in the anode circuit of the tube, which are amplified and transferred to the grid 6 of a discharge tube 5 comprising, in addition, to the grid, an i-ncaiidescent cathode 7 and an anode 8., The circuit arrangement used for transmitting the ampli.- fied oscillations is known per se and is only illustrated to enable a good understanding of' the invention.

In the anode circuit ofthe tube 1 are inserted a battery 9 and an anode resistance 10.

A condenser 11 connects one end of said resistance to the grid 6 and, between. this grid and the incandescent cathode 7 are interposed a leakage resistance 12 and a battery 13. The two incandescent cathodes ofthe tubes 1 and 5 are connected by a conductor 14.

Thev current variations. in the anode circuit of the tube 1 set up tension fluctuations at the ends of the anode resistance 10 which by the condenser 11 are transmitted to the grid circuit of the discharge tube 5.

According to the invention the amplifyin resistance 10 the condenser 11 and the lea age resistance 12 connected in a correct manner constitute a self-contained unit provided with four contact-making members which correspond to the points A, B, C and D. In an amplifying installation it is therefore possible to interpose between every two successive discharge tubes' an apparatus according to the invention, which ensures a much simpler mounting of a receiving installation.

In the construction according to Fig. 2 the condenser 11 is constructed as a Wound condenser, which is arranged within a vessel 2O of insulating material such as glass. The space between the condenser and the vessel 20 is filled with paraiiin. On the outer wall of the vessel 20 are wound the resistances 10 and 12. These resistances consist of resisting wire, constantan for example, which is helically wound on a core of insulating material, such for example, as asbestos or yarn. The two ends of each resistance are connected to four contact-pins 21 secured in the disc 22 of insulating material. The disc 22 is connected by a metal ring 23 to a glass bulb 24 surrounding the aforementioned members.

In the construction according to Figure 3 the condenser 11 and the resistances 10 and 12 are arranged within a closed exhausted vessel 25. The condenser 11 is a Wound condenser slid on a glass rod 26 which is secured on a glass stem tube 27. The resistances 1() and 12 which consist, for example, of silite rods are likewise secured to the stem tube 27, whereas the four leading-in wires leading to the two ends of each resistance are hermetically sealed in the pinch of the stem tube 27. The four leading-in wires are connected i to four contact-pins 28 which are secured to the glass vessel 25 in a manner similar to that shown in Figure 2.

I The invention can also be carried into effect when tetrodes instead of triodes are used, in which case the circuit arrangement is essentially the saine as before described.

Vhat I claim is A coupling unit comprising an anode resistance, a leakage resistance, and a grid condenser, the condenser being arranged within a hollow glass vessel and the space between the condenser and the hollow glass vessel being filled with paraffin, the resistance elements being wound aboutthe exterior of the glass vessel, the whole being enclosed in a vacuum tube having four Contact pins to fit into the usual socket, the contact pins being connected with the respective ends of the resistance elements.

4In testimony whereof I affix my signature at the city of Eindhoven, this 22nd day of April, A. D. 1925.

BALTHASAR VAN DER POL. 

